OBJECTIVES: 1. Tritium labeling, chemical modification, proteolysis and various separation and spectroscopic techniques will be employed for labeling, release and identification of fluorescent and non-fluorescent chromophores, Schiff-base type and gamma-glutamyl-epsilon-Lysine linkages in the normal, aged and cataractous human lens. 2. Transglutaminase of normal guinea pig lens will be purified by hydrophobic affinity chromatography and its polymerizing activity on lens proteins will be determined. 3. The action of Ca-ionophore A23187, pharmacologically active and hydrophobic amines on the endogenous activity of transglutaminase of guinea pig lens in culture, will be investigated. 4. The relationship of transglutaminase activity of X-ray-induced cataractous lens to the levels of Ca, glutathione, Ca ATPase and Lysosomal proteases will be determined.